The present invention relates to a method and an apparatus for maintaining or restoring freshness of vegetable bodies such as plants, vegetables, fruits, flowers, flowering plants and leaves. Furthermore, the present invention relates to a method and an apparatus for planning to maintain or restore freshness of vegetables and fruits.
Methods of preserving freshness of vegetables and fruits have heretofore been practised such as a method, wherein the vegetables and fruits are immersed into or sprayed with cold water or cold brine. Due to the lowered temperature of the vegetables and fruits, living functions thereof are controlled namely, consumption of activated physiological energy is avoided by a reduced respiration value, evaporation is controlled and deteriorated product quality due to withering and the like is prevented.
Numerous variations of this technique have been proposed.
Several examples of these proposals are listed here, and differences thereof from the present invention will hereunder be described.
Japanese Patent Laid-Open (Kokai) No. 35165/72 discloses a method wherein the vegetables and fruits are immersed in or sprayed with an aqueous solution containing 0.2-1.0% of sodium acetate, said aqueous solution being added thereto with low concentration brine,
Japanese Patent Laid-Open (Kokai) No. 159783/80 discloses a method wherein the vegetables and fruits are vacuum-treated, subsequently, sprayed with cold water, and thereafter, stored under reduced pressure.
Japanese Patent Laid-Open (Kokai) No. 131345/80 discloses a method wherein the vegetables and fruits are immersed in hypochlorous acid solution, rinsed with water, thereafter, immersed in anti-oxidant bactericidal water, and then, dehydrated and stored,
Japanese Patent Laid-Open (Kokai) No. 159783/80 discloses a method wherein the vegetables and fruits are put into a vacuum tank, a cold water layer is formed on the surface of the vacuum tank by spraying to generate micromist in the vacuum tank, thereafter, the vacuum tank is drawn vacuum, cooled and stored, and
Japanese Patent Laid-Open (Kokai) No. 113227/81 discloses a method wherein the vegetables and fruits are passed through cold water showering, and placed in a refrigerator under low temperature and high humidity, to thereby hold freshness thereof.
All of the above-described proposals require considerably complicated apparatus which can lead to troublesome operations.
The following proposals disclose methods wherein, when stored, the vegetables and fruits are brought into contact with various additives for holding freshness.
Japanese Patent Laid-Open (Kokai) No. 60940/83 discloses a method wherein the vegetables and fruits are brought into contact with zeolite, silicic acid clay and the like,
Japanese Patent Laid-Open (Kokai) No. 143576/84 discloses a method wherein the vegetables and fruits are coated or sprayed with a member selected from the group consisting of L-ascorbic acid, ferrous sulfate, ferrous chloride and ferrous nitrate,
Japanese Patent Laid-Open (Kokai) No. 24152/85 discloses a method wherein the vegetables and fruits are immersed in or sprayed with an aqueous solution containing 1 weight part of lecithin taken to 10-5,000 weight parts of water, said lecithin being mixed with and dispersed in the water, and
Japanese Patent Laid-Open (Kokai) No. 49740/85 discloses a method wherein cold water is added thereto with 1-2 weight % of a member selected from the group consisting of propylene, glycol-glycerine-ethanol and salts as an antifreeze and 2-5 weight % of zeolite as a dehydrating agent.
It cannot be said that there are no problems about the additives themselves, and much consideration may be still required for holding freshness of the food products.
As methods wherein the vegetables and fruits are placed in a sealed vessel containing therein any one of various gases so as to hold the freshness thereof, there are methods as follows.
Japanese Patent Laid-Open (Kokai) No. 153753/85 discloses a method wherein the vegetables and fruits are placed in a gaseous atmosphere of any one of saturated hydrocarbons such as propane and butane or any one of halogenated hydrocarbons such as trichlorofluoromethane and trichlorotrifluoroethane, and
Japanese Laid-Open (Kokai) No. 75756/74 discloses a method wherein the vegetables and fruits are stored in a sealed vessel in which gaseous values of nitrogen and oxygen differ from each other in accordance with the types of the vegetables and fruits.
These methods have various problems including the sealed vessel itself, the relationship between the sealed vessel and the gas generator, and the like.
In the case where cold water is used or brine is added to cold water in the above-described prior art, due to absorption of moisture and the like to some extent, evaporation of moisture from the vegetables and fruits can be controlled. However, remarkably improved freshness cannot be obtained. Furthermore, as for the cold brine, regulation of brine concentration (within several percent order) is needed in accordance with the types of the vegetables and fruits and the usage of salt amounts to a high value, so that this method cannot be recognized to be an easy and economical method.
As described above, according to the prior art, the apparatus and vessels require high costs and problems are involved in blending of additives and the relationship between the additives and food products, and further operating procedures are complicated as well.
In view of the above-described problems, the present invention has been achieved as the results of various studies to develop a method and an apparatus which affords greater economy by using a simple apparatus that is easy to operate.